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Discussion Starter #1
I'm having an issue with setting up my vdyno properly, I can feel a difference with OVtune (in progress) but want to check some actual numbers from the runs I got. I know they won't be 100% but I would like to see.

Problem is the results are all over the chart with the graph doing all kinds of funny things as far as low hp/tq to impossible numbers all in the same graph which looks like a roller coaster.
I have the weight, wheel size and gearing but it just seems something is messing it up royally that I haven't figured out.

Anyone know exact parameters I should put in that would provide realistic and consistent results?
 

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I'm having an issue with setting up my vdyno properly, I can feel a difference with OVtune (in progress) but want to check some actual numbers from the runs I got. I know they won't be 100% but I would like to see.

Problem is the results are all over the chart with the graph doing all kinds of funny things as far as low hp/tq to impossible numbers all in the same graph which looks like a roller coaster.
I have the weight, wheel size and gearing but it just seems something is messing it up royally that I haven't figured out.

Anyone know exact parameters I should put in that would provide realistic and consistent results?
Have a read through of this thread which discusses settings and the things to look out for when logging so that you can make decent tune file comparisons. If the logs are not made at the exact same flat location under similar temperatures and wind, you will likely see variations in the curves that are not caused by actual changes between tune files. You also get better results with 3rd, rather than 2nd gear runs, and you should always go WOT around the same RPM point.

http://mazda3revolution.com/forums/...performance/128210-vdyno-settings-ovtune.html


Example of what a small down hill stretch would do to the Vdyno at the end of a WOT run:

http://mazda3revolution.com/forums/...rformance/128210-vdyno-settings-ovtune-2.html
 

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Discussion Starter #3 (Edited)
Thanks. Much better results, it was the road I was on. I though it might have been fine but I was way off.

Here is a before and after on the same tune ( was using 2nd in auto mode, used manual mode in third for new log / better ground) Both logs are on the same tune file.
 

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Thanks. Much better results, it was the road I was on. I though it might have been fine but I was way off.

Here is a before and after on the same tune ( was using 2nd in auto mode, used manual mode in third for new log / better ground) Both logs are on the same tune file.
Wow, that previous Vdyno looks pretty crazy lol. Looks like it shifted in the middle of the run which produced that big swirl that distorts power that could be achieved... I'm glad you got it figured out. My friends with auto also use manual mode, and go WOT around 2500ish rpm in 3rd, and it seems to hold the gear all the way to redline :) Its important to hit the gas pedal kick-down switch fairly fast, as this triggers full throttle enrichment which will give you maximum torque early in the Vdyno. It will also make it easier for the tuner to diagnose any potential problems, and dial in the whole rpm band more accurately.
 

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Discussion Starter #5
Yeah, bad spot late kick down so it went to first then second in auto. I'm going to do third in manual from now on. Will have to find the kick down timing so it doesn't cause shifting. Thanks again for the info.
 

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I don't know what the lower of the two pictures is showing but does anyone else agree that the engine doesnt do anything from 4000-6500 rpm? All the torque seems to be between 2000-3500 rpm, which is what that red line on the lower image kinda matches.

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I don't know what the lower of the two pictures is showing but does anyone else agree that the engine doesnt do anything from 4000-6500 rpm? All the torque seems to be between 2000-3500 rpm, which is what that red line on the lower image kinda matches.

Sent from my LG-H631 using Tapatalk
The blue tq & hp lines don't represent the cars true power levels, as the trans shifted in between the run, causing them to fall off and swirl. That graph is basically meaningless for comparison.

The red lines depict a better WOT recording. As the torque curve is relatively flat, it would suggest that the car builds power steadily from around 3000 rpm to the top-end. It shows a smooth power delivery across the rpm range rather than all top end focused power that you would see in some older Honda's; "Vtech just kicked in"...
 

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...er, ok but can we agree that when the engine runs between 4000-6500 rpm, it's just making noise and doesn't push at all compared to 2000-4000?

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...er, ok but can we agree that when the engine runs between 4000-6500 rpm, it's just making noise and doesn't push at all compared to 2000-4000?

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I'm not sure how you are coming to that conclusion. Ignore all the blue lines posted. The red shows that torque curve is fairly flat from 3000-5500 rpm, and still building below 3000 rpm. The car will accelerate the hardest when the rpm is near its peak torque which almost gets achieved throughout 3000-5500, as torque is relatively flat. It's lowest when its furthest from the peak (typically very low and high rpms). A flat torque curve means that you will get similar acceleration when you are pushing through the flat portion of the curve (not factoring in high speed air/drag resistance that slows you down). So the car would be pulling similarly all the way from 3000-5500 rpm, after which acceleration will drop-off towards redline. Its true that going far over 6000 rpm will hinder acceleration.
 

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I'm not sure how you are coming to that conclusion. Ignore all the blue lines posted. The red shows that torque curve is fairly flat from 3000-5500 rpm, and still building below 3000 rpm. The car will accelerate the hardest when the rpm is near its peak torque which almost gets achieved throughout 3000-5500, as torque is relatively flat. It's lowest when its furthest from the peak (typically very low and high rpms). A flat torque curve means that you will get similar acceleration when you are pushing through the flat portion of the curve (not factoring in high speed air/drag resistance that slows you down). So the car would be pulling similarly all the way from 3000-5500 rpm, after which acceleration will drop-off towards redline. Its true that going far over 6000 rpm will hinder acceleration.
I'm coming to that conclusion because that's how the car feels when I'm on the freeway onramp accelerating from 20mph to 50mph and watching the tachometer. All of the engine pull happens below 4,000rpm. above that, and the engine is just making noise, not increasing the acceleration of the vehicle with the same force as it does below 4,000rpm. Maybe i'm alone in that thought, but i've seen a bunch of youtubers also make that same comment when they review the 3. The engine is torque-y until around 4,000 rpm and then it just doesn't pull with the same force as it does in the lower-mid rpms.
 

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I'm coming to that conclusion because that's how the car feels when I'm on the freeway onramp accelerating from 20mph to 50mph and watching the tachometer. All of the engine pull happens below 4,000rpm. above that, and the engine is just making noise, not increasing the acceleration of the vehicle with the same force as it does below 4,000rpm. Maybe i'm alone in that thought, but i've seen a bunch of youtubers also make that same comment when they review the 3. The engine is torque-y until around 4,000 rpm and then it just doesn't pull with the same force as it does in the lower-mid rpms.
Do you have a 2.0 or 2.5L? The 2.5L seems to have much more grunt below 4,000 rpm compared to above 4,000, and this is reflective of its more sloping torque curve (torque falls off fast after 4000 rpm). I notice this on my 2.5L CX-5... The 2.0L has less low-end relative to the 2.5L, and the low-end is more balanced with the mid-range in the 2.0 (flatter torque curve), which makes the power feel more linear, and less lacking in the top-end even though it has less of it. Skyactiv engines are built for low-end torque rather than top-end based on their small cylinder head intake & exhausts ports, and high velocity exhaust design. They were designed more for daily driving rather than top-end racing. I can't think of any other engine in the same class which has so much torque at just ~3,000 rpm NA...
 
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